Compositions of a polycarbonate resin and polypropylene are described in U.S. Pat. No. 3,801,673. These compositions are useful for many purposes but have been shown to produce molded articles that do not provide good weld line strength as measured in a double gate impact test. Various block copolymers of a polyphenylene oxide and a carbonate containing polymeric unit have been described in U.S. Pat. Nos. 3,875,256 and 3,703,564. These patents describe many techniques for forming various types of block copolymers and mention that these copolymers may be combined with various types of polystyrenes.
The applicants have found that a block copolymer containing a polyphenylene oxide block and a polycarbonate block derived from a dihydric phenol, are compatible with olefin polymers as shown by enhanced double gate impact strength as compared to a polycarbonate-olefin composition.